In their 1950s heyday, soda jerks hollered jargon such as “heavy on the hail” (extra ice) and “shot in the arm” (cola) at 100,000 soda fountains around the country.

About 125 traditional soda fountains survive today, and this fall local bartender Gina Chersevani is adding another with Buffalo and Bergen—a 15-stool bar at the new Union Market, DC’s answer to Philly’s Reading Terminal Market. Several other restaurants already serve from-scratch “pop.”

The Farmacy menu at the Potomac location of Founding Farmers includes a classic New York egg cream made from chocolate syrup, whole milk, and seltzer. Both El Chucho in DC’s Columbia Heights and Clarendon’s Green Pig Bistro take a more modern approach—there’s a tongue-searing spicy pineapple soda at El Chucho, while Green Pig offers sweet refreshers combining such flavors as blueberry and kaffir lime.

Soda is tricky, Chersevani says, because it’s hard to predict how a concoction will react mixed with, say, ice cream or vodka. “I want to thank my professors at the University of Maryland,” says the science student turned mixologist. “I thought then, ‘I’ll never use this stuff.’ I use it every day.”